Radbosia rubescens, a herbal medicine, has been traditionally used in China for the treatment of pharyngitis and esophageal carcinoma. Oridonin, the main pharmacological active substance of Rabdosia rubescens with various pharmacological and physiological effects, has drawn a rising attention for cancer biologists due to its remarkable anti-tumor activities. It has been reported that oridonin can induce apoptosis or autophagy in various kinds of cancer cells, such as multiple myeloma cells, colorectal cancer cells, hepatoma carcinoma cell, prostate cancer cells, cervical carcinoma cells and oesophageal cancer cells. These reports demonstrate the potent anti-cancer activity of oridonin against different cancer cells.
However, the clinical application of oridonin remains limited due to its low water-solubility and low bioavailability. Therefore, there is a need to provide an alternative formulation of oridonin to overcome the problem of low water solubility of oridonin and to increase its efficacy and bioavailability.
Selenium (Se) is one of the essential trace mineral elements found in various tissues and organs in the human body. The mineral is particularly important for the enhancement of immune response and prevention of cancer development. Se is mostly linked to Se-dependent enzyme or selenoprotein function. The risk of many cancers is decreased with Se supplementation and the side effect of radiotherapy can also be reduced by Se supplementation, indicating the potential application of Se compounds in cancer prevention and cancer treatment. With reduced risk of Se toxicity and excellent bio-activities, selenium nanoparticles have been widely developed in recent years in life sciences, especially their potential use in cancer treatment. Firstly, selenium nanoparticles could be used as protection agents to protect the normal cells from the cytotoxicity of anti-cancer drugs. Secondly, selenium nanoparticles have strong cancer inhibition effects by inducing apoptosis of cancer cells. Thirdly, selenium nanoparticles could also be served as anti-angiogenesis agents, which could inhibit tumor growth by inhibiting new blood vessel formation.
Chitosan is a product resulting from the deacetylation of chitin, and is widely distributed in the carapace of shellfish or insects. Chitosan has been shown to associate with various pharmacological effects, including regulation of blood sugar level and blood fat level. As a natural product with high biocompatibility, safety, and biodegradability, chitosan is widely used in the field of medicine, food, chemical, cosmetic, water treatment, metal extraction and biomedical engineering.